Download UK Trends in Infectious Diseases

Number 545 January 2017
UK Trends in Infectious Disease
Overview
Infectious diseases can be transmitted from
animals to people, or from one person to
another. They can be mild and self-resolve, or
develop into more serious illnesses that if left
untreated lead to serious illness, long-term
consequences or death. This note looks at UK
trends in infectious disease.
Background
Vaccination, antimicrobial drugs and improved hygiene
mean that infectious disease has been overtaken by noncommunicable disease (cancer, cardiovascular disease and
diabetes) as the main cause of death globally and in the
UK.1 However infections are still a significant health and
economic burden to the UK.2 This POSTnote describes
recent trends in infections of particular concern in the UK. It
outlines the trends that largely result from the capacity of
infectious pathogens (disease causing agents) to develop
resistance to existing drugs, the emergence of new
infections and the re-emergence of infections linked to
health inequalities or other factors. Infections are caused by
viruses, bacteria, fungi, protozoa, parasites or prions. The
epidemiology (causes, patterns and effects) of infectious
disease are determined by the interplay of numerous
factors: the individual (sex, age [see Box 1], health status,
immunity and behaviour), the pathogen (its pathogenicity
and ability to mutate) and the environment (climate, air
quality and socio-economic factors such as income, quality
of nutrition and housing).
Impact of Infectious Disease in the UK
There is no recent single analysis of the overall health
burden of infectious disease in the UK, but data on
individual infections are available from various sources. The
Chief Medical Officer (CMO) has estimated that, in 2010,
infectious diseases accounted for 7% of all deaths, 4% of all
 Infectious diseases are a significant health
and economic burden in the UK, accounting
for 7% of deaths and annual costs of £30bn.
 The national immunisation programme is
widely considered to be the most effective
public health intervention in the UK.
 There are a number of infections of
particular public health concern for the UK
for which there are vaccines in the early
phases of development.
 Another area of policy interest is
antimicrobial resistance. Few of the most
needed new drugs are currently in
development.
 Health inequalities continue to be a
significant contributory factor in poor health
outcomes for those people in the lowest
socio-economic groups.
potential life years lost and 8% of hospital bed days.
Infections are responsible for a large proportion of sickness
absence from work. For example, minor illnesses such as
respiratory or gastro-intestinal infections are the most
common reason for work absence, accounting for 27.4m
days lost in 2013.3 The total economic burden from
infectious diseases in England is estimated at £30bn
annually (this includes costs to the health service, the labour
market and to individuals).2
Surveillance of Infectious Disease
Public Health England (PHE) is responsible for detecting
outbreaks of disease and epidemics, with equivalent
counterparts in the devolved administrations.4,5,6 National
and international approaches to monitoring and surveillance
have been described in detail in a previous POSTnote.7
Preventing Infectious Disease
The National Institute for Health and Care Excellence
(NICE) provides advice on cost-effective healthcare. NICE
guidelines outline evidence-based best practice for infection
control in community and hospital care settings.8,9 There is
detailed advice on hand washing, managing the use of
antimicrobial drugs (discussed later), organisational
responsibilities (such as co-ordinating infection control
strategies), education of health care workers and for the
management of specific interventions where infections are
common, notably catheters or devices inserted into veins.
The Parliamentary Office of Science and Technology, Westminster, London SW1A 0AA; Tel: 020 7219 2840; email: [email protected] www.parliament.uk/post
POSTNOTE 545 January 2017 UK Trends in Infectious Disease
Box 1. Infections and the Connection to Life Stages
The Chief Medical Officer’s 2011 report on infectious disease
highlighted the connection between infections and life stages2:
 Perinatal Infections - babies’ immature immune systems are
susceptible to infections. They can be contracted in the womb,
during labour, or immediately after birth and are associated with
increased mortality and illness.10 Perinatal infections cause an
estimated 10% of stillbirths and can also cause premature birth
(premature babies are also more likely to develop an infection).10
Mother-to-baby HIV transmission has reduced from 25.6% in
1993 when there were no interventions, to <0.5% now, through
ante-natal screening and anti-retroviral drug therapy for HIVpositive pregnant women. Immunisation of newborn babies
whose mothers have the blood-borne virus hepatitis B has
reduced transmission by 95%, and prevented cases of liver
disease, cirrhosis and cancer in children and young adults.
 Infancy and Childhood - children are prone to infections as the
immune system develops, mainly through exposure to
pathogens, via close contact with other children at nursery and
school. The UK national immunisation programme11 offers a
course of vaccinations that protect children (and the wider
population) from a range of potentially serious illnesses.
 Adolescence and Adulthood - behavioural factors are key
contributors to the spread of infections at this life stage. For
example the risk of contracting sexually transmitted infections is
largely dependent on sexual behaviour. For some infections,
drug use involving contaminated needles is also a risk.
 Old Age - immune system function declines with age, so the
rising UK elderly population is more susceptible to infections.
They may also be at greater risk of exposure to pathogens
because of frequent interactions with healthcare, or by living in
settings such as care homes that bring them into contact with
other people.
Immunisation
Immunisation is the process by which people are made
immune to an infectious pathogen. It is widely considered as
the most effective public health intervention. When coverage
is high enough, infections can be eliminated, such as with
smallpox. Where coverage is insufficient, the risk of infection
re-emerges, for example as seen in the 2013 measles
outbreak in South Wales.12 The NHS immunisation schedule
provides vaccines to protect against infectious diseases,
from the pre-natal period, through infancy, childhood,
adolescence and into old age. The Government is advised
on immunisation by the Joint Committee on Vaccination and
Immunisation (JCVI). JCVI makes recommendations about
whether it is cost-effective to add vaccines to the national
programme and proposes changes to the existing schedule.
These recommendations are made in response to changes
in the epidemiology of disease and the availability of new
vaccines.13 For example, immunisation against meningitis B
is now available for infants who are most at risk from the
infection.14,15 Other recent additions to the national
programme include vaccines against pertussis (whooping
cough) and rotavirus, both of which have led to fewer cases
and reduced mortality rates.16,17,18,19,20 Monitoring levels of
immunisation is needed to identify where coverage is
inadequate. For example trends in coverage of the measles,
mumps and rubella (MMR) vaccine for children aged two
are shown in Figure 1. Coverage was 91.9% by 2015,21 and
has increased steadily since 2009, but is still below the
World Health Organisation target of at least 95%.
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100
World Health Organisation target coverage
95
90
85
80
75
1998
2000
2002
2004
2006
2008
2010
2012
2014
Figure 1. Trends in % coverage with MMR immunisation at 24
months old, England and Wales, 1998–2015
Priorities for Immunisation and Vaccine Development
JCVI priorities for future vaccine programmes are Group B
Streptococcus and respiratory syncytial virus (RSV). Group
A and B streptococci mainly cause minor infections, but
babies are at particular risk from serious Group B infections.
RSV is a common cause of serious respiratory infections in
infants and the elderly. Vaccines are in clinical trials for
common healthcare-acquired infections (S. aureus, C.
difficile and Pseudomonas aeruginosa), hepatitis C, RSV,
Group B streptococcus, norovirus, Lyme disease and
cytomegalovirus (CMV).22 JCVI is also interested in vaccine
development for norovirus, methicillin resistant S. Aureus
(MRSA), CMV, hepatitis C and typhoid.23,24
Healthcare-Acquired Infections
Healthcare Acquired Infections (HCAIs) are common, and
may result in illness, prolonged hospital stays or death.
There is mandatory surveillance of the bacteria responsible
for the bloodstream infections caused by MRSA, C. difficile
and E. coli. Table 1 summarises data on reported cases of
each. A recent 6% rise in C. difficile cases was the first
annual increase since 2007. Mandatory surveillance of E.
coli infections began in 2012/13, and have risen by 10.4%
since. The rate of infections per 100,000 population is a
useful comparator: in 2015/16 it was 70.1 for E coli, much
higher than the 1.5 for MRSA.25
C. difficile
E. coli
2007/08
55,498
No data
2008/09
36,095
No data
2009/10
25,604
No data
2010/11
21,707
No data
2011/12
18,022
No data
2012/13
14,694
32,309
2013/14
13,362
34,275
2014/15
14,192
35,764
2015/16
14,139
38,132
Table 1. Cases of healthcare-acquired infections25
MRSA
4,451
2,935
1,898
1,481
1,116
924
862
800
819
Interventions such as hygiene measures (behaviour change
such as hand-washing and cleaning protocols, and design
of hospitals and equipment), improved antibiotic prescribing
and changes to some surgical techniques, have reduced the
burden of HCAIs. One focus is to take a preventative
approach to bacteria such as E. coli, Pseudomonas and
Klebsiella which are harder to treat, becoming more
prevalent and cause urinary tract and bloodstream
POSTNOTE 545 January 2017 UK Trends in Infectious Disease
Hepatitis C
Hepatitis C is a treatable but chronic blood-borne infection
that affects liver cells. There is no vaccine. The number of
confirmed cases of hepatitis C infection has risen more than
five-fold in England since the 1990s, with 1,836 new cases
per year between 2011–2015.26 An estimated 200,000
people have the infection in the UK, half of whom are
undiagnosed. Left untreated, serious liver disease and
cancer can occur, with a transplant the only option.
Admissions to hospital rose from 611 in 1998 to 2,658 in
2012, with a similar increase in mortality, rising from 98 in
1996 to 457 in 2014.27 The number of liver transplants in the
UK as a consequence of the infection has also risen from 45
in 1996 to 175 in 2014 (17% of all liver transplants).27
One of the biggest risk factors for contracting hepatitis C is
injected drug use: anonymised surveys show that of people
who inject drugs, 50% in England, 23% in Northern Ireland
and 57% in Scotland have the infection. These rates have
been stable for the last decade. The rate in Wales has risen
from 19% in 2003 to 47% in 2014.27 Policy approaches
focus on preventing new infections, raising awareness of the
virus, improving and increasing diagnoses, and treatment
with anti-viral drugs. It is expected that new direct acting
antiviral drugs for hepatitis C will improve health outcomes;
a reported 11% decreased in mortality in 2015 is attributed
to them.26 Testing those most at risk continues to be a
priority, including former and current injecting drug users.
Sexually Transmitted Infections
Sexually transmitted infections (STIs) almost always occur
via unprotected sex. There were 435,000 diagnoses of STIs
in England in 2015.28 Chlamydia is the most common STI
(200,228 diagnoses in 2015), with many people unware of
their infection. If left untreated, it can cause long-term health
problems, including infertility. Other common STIs in 2015
were genital warts (68,310 diagnoses), gonorrhoea (41,193
diagnoses) and genital herpes (33,218 diagnoses).29 In
2015, heterosexual men and women accounted for 92% of
diagnoses of genital warts, 92% of genital herpes and 85%
of chlamydia diagnoses, while men who have sex with men
(MSM) accounted for 79% of syphilis and 54% of
gonorrhoea diagnoses.28 Overall, new diagnoses of STIs fell
by 3% between 2014- 2015. This fall is thought to be
associated with fewer heterosexuals testing for chlamydia,
and fewer cases of genital warts in 15-19 year old females
as a consequence of the human papilloma virus (HPV)
immunisation programme. A continued trend is increased
rates of syphilis and gonorrhoea (rises of 76% and 53%
respectively since 2012), particularly in men.28 It is likely that
risky sexual behaviour accounts for these trends, although
gonorrhoea detection has also improved. The groups at
greatest risk of contracting infections are heterosexuals
aged under 25 and MSM, see Figure 2 for recent trends for
this group.
25
Chlamydia
20
genital herpes
genital warts
15
gonorrhoea
10
syphilis
5
0
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Figure 2. Trends in sexually transmitted infections in Men who have
Sex with Men, 2005-1530
HIV
There is no vaccine or cure for HIV, but prompt diagnosis
and antiretroviral drug treatment allows people a normal life
expectancy. Figure 3 shows the trend in new diagnoses of
HIV and AIDS and in mortality.31 The latest data from 2015
reported that 2015 101,200 people in the UK have HIV, with
an estimated 13% unaware of their infection.31 Late
diagnosis (after the immune system has been damaged)
has serious health effects, with half of heterosexuals (men:
55%, women: 49%) receiving a late diagnosis in 2015. New
HIV diagnoses in heterosexual men and women have
declined since 2004 with the overall prevalence in the
population in 2015 being 1.0 per 1,000.30 However this is
higher in heterosexual black Africans (men: 22.2 per 1,000,
women: 42.6 per 1,000) and MSM (58.7 per 1,000).31 Rates
of transmission remain high among MSM, with modelling
indicating that incidence could be increasing. There were
3,320 new diagnoses in MSM in 2014 (up from 2,860 in
2010), accounting for more than half of all new HIV
diagnoses. However the proportion diagnosed late has
decreased (43% in 2004 to 30% in 2015). Continuing the
downward trend in HIV transmission depends on a
combination of increasing testing availability and take up,
treatment and behaviour change (safer sex practices).32
Tailored prevention strategies and programmes are thought
to be particularly important for some at-risk groups.
10,000
AIDS
8,000
6,000
HIV
Deaths
4,000
2,000
0
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
2015
infections and life-threatening pneumonias. Another is on
infection control in settings outside hospitals, such as care
homes and in communities.
Page 3
Figure 3. Annual new HIV diagnoses, first AIDS diagnoses and deaths
in the UK, 1981–201531
Emerging Infections
The emergence of new infections and the re-emergence of
others are inevitable. They are a consequence of several,
often interacting factors:
POSTNOTE 545 January 2017 UK Trends in Infectious Disease




ecological and environmental factors - changes in
land use, water ecosystems and climate change (which
may affect the distribution of vector-borne diseases33)
human behaviour - travel, and the lack of or the
breakdown of public health measures
agricultural practices - intensive farming, animal
husbandry practices, unregulated use of antimicrobials
and international trade
microbial evolution.
An estimated two-thirds of emerging infectious diseases in
the last 60 years were zoonotic (passed from animal to
humans), with 70% coming from wild animals.34 PHE
monitors emerging patterns and assesses the possible
significance for public health.35 Monitoring includes
infections that arise in the UK, the spread of existing
infections into the UK or new infections that arise elsewhere.
Some emerging infections arise in tropical settings (such as
Ebola and Zika) whereas others arise elsewhere; recent
outbreaks of SARS, influenza A (H5N1) and foodborne E.
coli had non-tropical origins. Infections can have
implications for the UK even if cases do not occur here.
These include blood or tissue availability, extra demands on
healthcare, or health screening on entry to the UK, as with
the recent Ebola outbreak. Recent infections of concern
include the viral Middle East Respiratory Syndrome and
polio. Polio has been reported in Ukraine, which has low
rates of vaccination (50% coverage of children in 2014).36
Antimicrobial Resistance
Antimicrobial drugs, including antibiotics, anti-virals and antifungals are the main treatments for infections. Although
there are many effective antimicrobials against both bacteria
and viruses, drug resistance, largely driven by inappropriate
prescribing, is a serious threat to public health.37 A recent
review raised concerns that deaths due to antimicrobial
resistance could outweigh mortality from all other causes by
2050, if action is not taken (0.7m annual deaths worldwide,
rising to a possible 10m annual deaths in 2050).38
Drug resistance can be minimised by ensuring that drugs
are used only when necessary. Resistance in bacteria which
cause most hospital-acquired and community infections
such as gonorrhoea39, are a serious concern since there are
limited treatment options and they are already resistant to
drugs of last resort. Drug-resistant TB is an increasing
problem in the UK, with some forms of the disease resistant
to multiple treatments.40 The Chief Medical Officer (CMO)
has described antimicrobial resistance as “catastrophic”,
and warned that if left untackled, could for example result in
people dying after minor surgery.41 The Government’s fiveyear, cross-departmental antimicrobial resistance strategy
outlines national and local objectives. The main aims are:
 improved knowledge of antimicrobial resistance
 better stewardship of existing drugs
 stimulating development of new diagnostics (to identify
infections accurately) and drugs, particularly
antibiotics.42
Page 4
Development of new antibiotics has declined in recent
decades.43,44 This reflects the complexities of designing
effective drugs, the significant rate of attrition as compounds
are tested and rejected, and lower returns for
pharmaceutical companies’ investment, compared with
other medicines. The latter arises from the fact that new
antibiotics are unlikely to be sold in volume: treatments are
short-term (usually a few days) and likely to be held in
reserve as a last resort. An estimated 40 new antibiotics are
currently in development.45 These are not of the kind most
urgently needed; broad-spectrum agents (active against a
range of microbes) and which are capable of overcoming
multiple mechanisms of resistance. Improved diagnostics
are also needed to identify pathogens in order to help
doctors to prescribe the right drug. 46,47
Health Inequalities
UK health inequalities result from social inequalities48
including differences in income, education, employment and
living conditions. The CMO has identified infectious
diseases which exemplify health inequalities in the UK.
 Tuberculosis is concentrated in the most deprived
areas. In 2015 the rate of TB was 20.5 per 100,000 in
the 10% of the population living in the most deprived
areas and 3.6 per 100,000 in the 10% in the least
deprived areas.40 Those most at risk are those who are
not UK-born, have a history of drug use, imprisonment
or homelessness. Such groups are at highest risk of
transmission and acquiring drug-resistant strains and
least likely to complete treatment. They are also more
likely to have other infections, such as hepatitis B or C.
 STIs are particularly concentrated in deprived urban
areas. Diagnoses of gonorrhoea rose by 11% between
2014 and 2015, and are concentrated in the most
deprived areas of London.49 HIV rates are also highest
in deprived areas, especially in London.
Immunisation and Inequalities
Inequalities are associated with low vaccine take up (Box
2).50 Research suggests that interventions to improve
vaccination take up at population level are unlikely to make
a difference to some groups, for whom specific polices are
needed. There is no government policy to reduce the
influence of inequalities on the prevalence of infectious
disease, or health more generally. However NHS England
recognises the challenges51 and national public engagement
work is underway.52
Box 2. Factors Underlying Inequalities in Vaccine Take Up
Children most at risk of not being fully immunised are:
 those who missed previous vaccinations (whether as a result of
parental choice or otherwise) or not registered with a GP
 those with physical or learning disabilities
 children of teenage or lone parents and looked after children
 younger children from large families
 children who are hospitalised or have a chronic illness
 children from some minority ethnic groups
 vulnerable children, such as those whose families are travellers,
asylum seekers or are homeless.
POST is an office of both Houses of Parliament, charged with providing independent and balanced analysis of policy issues that have a basis in science and technology.
POST is grateful to all contributors and reviewers. For further information on this subject, please contact the author, Dr Sarah Bunn. Parliamentary Copyright 2017. Image:
Neisseria gonorrhoeae, the bacterium responsible for the sexually transmitted infection gonorrhoea, image copyright Dr David Phillips/Visuals Unlimited.
POSTNOTE 545 January 2017 UK Trends in Infectious Disease
Endnotes
1 In press, Trends in Non-Communicable Disease, Parliamentary Office of
Science and Technology
2 Annual Report of the Chief Medical Officer, Volume Two, Infections and the
Rise of Antimicrobial Resistance, 2011
3 Sickness Absence in the Labour Market, February 2014, Office for National
Statistics
4 Health Protection Scotland
5 Public Health Wales
6 Department of Health, Social Services and Public Safety, Northern Ireland
7 Surveillance of Infectious Disease, POSTnote 462, Parliamentary Office of
Science and Technology, 2014
8 NICE Quality Standard on Infection Prevention and Control QS 61, National
Institute for Health and Care Excellence
9 NICE Guideline CG139 Healthcare-Associated Infections: Prevention and
Control in Primary and Community Care, March 2012
10 Infant Mortality and Stillbirth in the UK, POSTnote 527, Parliamentary Office of
Science and Technology, 2016
11 Childhood Vaccination Programme, POSTbrief 13, , Parliamentary Office of
Science and Technology, 2015
12 Outbreak of Measles in Wales Nov 2012 – July 2013, Public Health Wales
13 Joint Committee on Vaccination and Immunisation
14 NHS Choices, Men B Vaccination
15 JCVI position statement on use of Bexsero® meningococcal B vaccine in the
UK, Department of Health and Public Health England, March 2014
16 Childhood Immunisation Programme, POSTbrief Number 13, September 2015
17 Pertussis: guidance, data and analysis, Public Health England
18 Vaccination against pertussis (whooping cough) for pregnant women, Public
Health England
19 Rotavirus: guidance, data and analysis, Public Health England
20 Rotavirus vaccination programme for infants, Public Health England
21 NHS Immunisation Statistics England 2015-16, Health and Social Care
Information Centre, 22 September 2016
22 Vaccine pipeline data supplied to POST by the ABPI Vaccine Group
23 Minute of the meeting on 4 June 2014, Joint Committee on Vaccination and
Immunisation
24 Minute of the meeting on 3 June 2015, Joint Committee on Vaccination and
Immunisation
25 Annual Epidemiological Commentary: Mandatory MRSA, MSSA and E. coli
bacteraemia and C. difficile infection data, 2015/16, Public Health England, July
2016
26 Hepatitis C in the UK 2016 Report, Public Health England
27 Hepatitis C in the UK 2015 Report, Public Health England
28 Infection Report, Volume 10, Number 22, July 2016, Public Health England
29 Table 1: STI Diagnoses and Rates in England by Age and Gender 2006-2015,
2016, Public Health England
30 Table 2: New STI Diagnoses and Rates by Gender, Sexual Risk and Age
Group, 2011 - 2015, 2016, Public Health England
31 HIV in the United Kingdom: 2016 Report, Public Health England
32 Kirwan PD, Chau C, Brown AE, Gill ON, Delpech VC and contributors,
Preventing HIV in the UK, POSTnote 463, Parliamentary Office of Science and
Technology, 2014
33 Climate Change and Infectious Disease in Humans in the UK, POSTbrief 16,
Parliamentary Office of Science and Technology, December 2015
34 Heymann & Dar, Prevention is better than cure for emerging infectious
diseases, BMJ 2014; 348
35 Infectious Disease Surveillance and Monitoring for Animal and Human Health:
Summary of notable incidents of public health significance. Monthly reports are
published by Public Health England.
36 Circulating vaccine-derived poliovirus – Ukraine, Disease Outbreak News,
September 2015, World Health Organisation
37 Antimicrobial Resistance Empirical and Statistical Evidence-Base, A report
from the Department of Health Antimicrobial Resistance Strategy Analytical
Working Group, September 2016
Page 5
38 Antimicrobial Resistance: Tackling a Crisis for the Health and Wealth of
Nations The Review on Antimicrobial Resistance, Chaired by Jim O’Neill,
December 2014
39 Outbreak of high level azithromycin resistant gonorrhoea in England: an
update, Infection report, Volume 10 Number 30 Public Health England,
September 2016
40 Tuberculosis in England 2016 report (presenting data to end of 2015), Public
Health England
41 Antimicrobial resistance poses ‘catastrophic threat’, says Chief Medical Officer,
Press Release, Department of Health, 12 March 2013
42 UK Five Year Antimicrobial Resistance Strategy 2013 to 2018, Department of
Health and Department for Environment, Food and Rural Affairs, 2013
43 The Threat of Antibiotic Resistance, The Pew Charitable Trusts, May 2014
44 US Food and Drug Administration, Drug Approval Reports
45 Antibiotics Currently in Clinical Development, The Pew Charitable Trusts,
December 2016
46 Securing New Drugs for Future Generations: the Pipeline of Antibiotics, The
Review on Antimicrobial Resistance, Chaired by Jim O’Neill and published by
the Wellcome Trust and HM Government, May 2015
47 Tackling Drug-Resistant Infections Globally, The Review on Antimicrobial
Resistance, Chaired by Jim O’Neill and published by the Wellcome Trust and
HM Government, May 2016
48 Fair Society Healthy Lives, The Marmot Review, Strategic Review of Health
Inequalities in England post-2010
49 Infection Report, Volume 10, Number 22, Health Protection Report, Weekly
Report, Public Health England
50 Reducing Differences in the Uptake of Immunisations, NICE Guideline PH21
2009
51 Board Paper NHSE121313, NHS England
52 National Conversation on Health Inequalities, Public Health England